Method and apparatus for discharging works from a centerless grinder

ABSTRACT

Method and apparatus for discharging works  2, 2   a  from a centerless grinder  1  are provided, wherein the works are through-fed to the centerless grinder  1,  processed with grinding therein, aligned axially along the horizontal direction on a guide plate  3  disposed on the work discharging side of the centerless grinder  1,  and pushed out of the front end of the guide plate  3  by means of thrust force provided during the grinding, whereby the works  2  are caused to fall, by means of the own weight thereof, onto a discharge chute  5  disposed below. The method comprises steps of: (a) pressing downward vertically the upper end of the circumferential surface of a preceding work  2  of the works being pushed out of the guide plate  3  by means of a roller  4  energized with a spring  13;  and (b) causing the preceding work  2,  that has been completely pushed out of the guide plate  3,  to fall, while bringing the front end of the preceding work  2,  that has been completely pushed out of the guide plate  3,  in contact with the contact surface  7  of a stopper  6  that hangs in front of the front end of the guide plate  3,  swingably in the direction of the works  2  being pushed out. The stopper  6  is adapted not to swing in case that only the preceding work  2  has been completely pushed out of the front end of the guide plate  3,  and the stopper  6  is adapted to swing in case that one following work  2   a  of the works, that is immediately following the preceding work  2,  is being pushed out of the front end of the guide plate  3  together with the preceding work  2,  whereby the horizontal component force from the stopper  6,  caused by the swinging motion, prevents the following work  2   a  from being pushed out together with the preceding work  2.    
     With method and apparatus for discharging works  2  from a centerless grinder  1  implemented as described above, advantages are effected in that the following work  2   a  of the works, that is immediately following the preceding or front work  2,  is prevented from falling together with the preceding work  2,  in case that the following work  2   a  of the works is being pushed out of the front end of the guide plate  3  together with the preceding work  2.  This is so effected because the preceding and following works  2, 2   a  being pushed out together cause the stopper  6,  in contact with the front end surface of the preceding work, to swing away from the front end of the guide plate  3,  which in turn causes a swing back motion, originating a horizontal component force on the contact surface  7  resisting to the works  2, 2   a  to be pushed out, whereby the following work  2   a  is prevented from having been completely pushed out until the preceding work  2  falls downward.

FIELD OF THE INVENTION

[0001] The present invention relates to a method and apparatus for discharging works from a centerless grinder, particularly to a method and apparatus for discharging axially-thin works from a centerless grinder, where the works are through-fed to the centerless grinder, processed with grinding therein, aligned axially along the horizontal direction on a guide plate disposed on the discharging side of the centerless grinder, and pushed out of the discharging end (or front end) of the guide plate by means of thrust force provided during the grinding, to be caused to fall onto a discharge chute disposed below, by means of their own weight.

BACKGROUND OF THE INVENTION

[0002] An apparatus is disclosed in Japanese Patent Unexamined Publication TokuKai-Hei (JP (A)) 8-19940, where, after axially-thin works are through-fed to a centerless grinder and processed with grinding therein, the works are aligned axially along the horizontal direction on a guide plate, and pushed out of the discharging end (or front end) of the guide plate by means of thrust force provided during the grinding, to be effected to fall onto a discharge chute disposed below, by means of their own weight, where the works are then conveyed by means of the discharge chute into a laser measuring device, where the works are passed through the laser measuring device in a radial direction to measure the outer diameter of the works for quickly feeding back the measuring results to the centerless grinder. In the method and apparatus for discharging works from a centerless grinder, as disclosed in the Japanese Patent Unexamined Publication, the works processed with grinding are aligned axially along the horizontal direction on a guide plate disposed on the discharging side of the centerless grinder, by means of thrust force provided during the grinding, and is caused to fall radially in the vertical direction, piece by piece, out of the discharging end (or front end) of the guide plate by means of air blow and their own weight, to be placed onto a discharge chute disposed below.

[0003] The disclosed apparatus has a disadvantage in that, while the axially-thin works ground and aligned on the guide plate disposed on the discharging side of the centerless grinder, and pushed out of the front end of the guide plate by means of thrust force provided during the grinding, neighboring works tend to be engaged with each other by means of grinding burr, whereby, if the grinding speed is increased, it becomes difficult to surely cause the works to fall, piece by piece, radially in the vertical direction, by means of air blow and their own weight, as the works are coming out of the front end of the guide plate, and chances are that two neighboring works fall double, or together. When the two works fall together, the discharge chute is clogged with the works resulting in transportation of the works to the measuring device being stopped. Then the works in the grinding process is caused to undergo processing for an excessive time, and, in turn, become defective. Once this condition occurs, the centerless grinder must be temporarily stopped for discharging all the unfinished works, and then restarted, which causes loss due to deterioration in yield and availability factor.

[0004] While a method is being implemented including steps of causing works to fall vertically in the radial direction of the works by pressing downward the works being pushed out of the front side of the guide plate, by means of a roller energized (given force) downward vertically with a spring, instead of air blow, such steps have not succeeded in solving the problem that two neighboring works pushed out of the guide plate tend to fall together, when the grinding speed is increased.

[0005] The present invention has been made to solve this problem. An object of the present invention is therefore to provide a method and apparatus for discharging works from a centerless grinder where the works, ground and being pushed axially along the horizontal direction out of a guide plate disposed on the discharging side of the centerless grinder, are surely caused to fall, piece by piece, radially in the vertical direction, even when the grinding speed is increased.

SUMMARY OF THE INVENTION

[0006] In order to accomplish the object described above, the present invention provides a method and apparatus for discharging works from a centerless grinder, wherein the works are through-fed to the centerless grinder, processed with grinding therein, aligned axially along the horizontal direction on a guide plate disposed on the discharging side of the centerless grinder, and pushed out of the front end of the guide plate by means of thrust force provided during the grinding, whereby the works are caused to fall, by means of the own weight thereof, onto a discharge chute disposed below. With the method and apparatus according to the present invention, the upper end of the circumferential surface of a preceding or front work of the works being pushed out of the guide plate is pressed downward vertically by means of a roller energized (given force) with a spring, and the preceding work having been completely pushed out of the guide plate is brought in contact with the contact surface of a stopper that hangs in front of the front end of the guide plate, swingably in the direction of the works being pushed out, whereby the preceding work is caused to fall. The stopper is adapted not to swing in case that only the preceding work has been completely pushed out of the front end of the guide plate. The stopper is adapted to swing in case that one following work of the works, that is immediately following the preceding work, is being pushed out of the front end of the guide plate together with the preceding work, whereby the horizontal component force from the stopper, caused by the swinging motion, resists the following work being pushed out of the front end of the guide plate, by means of the contact surface of the stopper, and prevents the following work from being pushed out together with the preceding work.

[0007] Thus, in case that the following work is being pushed out of the front end of the guide plate before the preceding work having been completely pushed out of the front end of the guide plate is caused to fall, the stopper is pushed away to swing. This swinging motion causes the horizontal component force in the stopper that pushes back the following work. Namely, the horizontal component force causes the contact surface of the stopper to press back the front end surface of the preceding work, which in turn pushes back the following work and prevents the following work from having been completely pushed out of the front end of the guide plate before the preceding work is caused to fall. This consequently prevents the two neighboring works from being discharged and falling together.

[0008] Preferably, according to one aspect of the present invention, a stand is disposed standing near the front end of the guide plate, where the stand has a lever fixed thereto, by means of a double holder. The lever includes a rocking center, one end on the side of the front end of the guide plate, and the opposite end, whereby the lever is fixed with the vertical position and the rocking center position of the lever made adjustable. The lever has the roller rotatably pivoted on the one end thereof, where the lever has a spring disposed between the opposite end thereof and the double holder, whereby the spring energizes the roller to vertically press downward the work being pushed out of the guide plate, in the radial direction of the work by placing the roller on the upper end of the circumferential surface of the work coming out of the front end of the guide plate. Under the free conditions, the roller is arranged to have the axis of the roller positioned in the same vertical plane as containing the front end surface of the preceding work that has been completely pushed out of the guide plate, and is arranged to have the lower end of the roller positioned slightly lower than the upper end of the circumferential surface of the preceding work before having been completely pushed out of the guide plate, respectively.

[0009] Furthermore, preferably, according to another aspect of the present invention, the stand is disposed standing near the front end of the guide plate, where the stand has a bracket fixed thereto. The bracket has the upper front end thereof extended upward, with the upper end of the stopper swingably pivoted on the upper front end of the bracket. The stopper has the lower end thereof equipped with the contact surface that makes light contact, under the free conditions, with the front end of the preceding work that has been completely pushed out of the guide plate, where the stopper has the lower end thereof further extended downward to form a guide surface approximately in parallel with the discharge chute. Specifically, under the free conditions, the stopper is arranged to have the contact surface thereof positioned in the same vertical plane as containing the front end surface of the preceding work that has been completely pushed out of the guide plate.

[0010] With method and apparatus for discharging works from a centerless grinder implemented as described above, advantages are effected in that the following work of the works, that is immediately following the preceding work, is prevented from falling together with the preceding work, in case that the following work of the works is being pushed out of the front end of the guide plate together with the preceding work. This is so effected because the two neighboring works, i.e., the preceding and following works, being pushed out together cause the stopper, in contact with the front end surface of the preceding work, to swing away from the front end of the guide plate, which in turn causes a swing back motion, originating a horizontal component force on the contact surface resisting to the works to be pushed out, whereby the following work is prevented from having been completely pushed out until the preceding work falls down.

[0011] Other objects and advantages of the present invention may become more apparent by referring to the following detailed description and accompanying drawings briefly described below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is an elevation view partly in section of a major portion of a centerless grinder equipped with an apparatus, according to an embodiment of the present invention;

[0013]FIG. 2 is an outside view along arrow lines 11-11 of FIG. 1; and

[0014]FIG. 3 is an elevation view corresponding to the elevation view partly in section of a major portion of a centerless grinder equipped with an apparatus, according to an embodiment of the present invention of FIG. 1, showing how the works are prevented from being discharged double, or together.

DETAILED DESCRIPTION OF THE INVENTION

[0015] The method and apparatus of the present invention will be described hereunder according to an embodiment shown in Figs. FIG. 1 is an elevation view partly in section of a major portion of a centerless grinder equipped with an apparatus, according to an embodiment of the present invention, and FIG. 2 is an outside view along arrow lines 11-11 of FIG. 1.

[0016] In a centerless grinder 1, axially-thin works are through-fed to the centerless grinder, processed with grinding therein, aligned axially along the horizontal direction on a guide plate 3 disposed on the discharging side of the centerless grinder 1, and pushed out of the front end of the guide plate 3 by means of thrust force provided during the grinding.

[0017] As the upper end of the circumferential surface of a preceding work 2 of the works being pushed out of the guide plate 3 is pressed downward vertically in the radial direction by means of a roller 4, the preceding work 2 is caused to fall by means of its own weight, to be discharged onto a discharge chute 5 below. In this case, the front end of the preceding work 2 having been completely pushed out of the guide plate 3 is only brought in light contact with the contact surface 7 of a stopper 6 that is disposed in front of the front end of the guide plate 3, because the stopper 6 is in a free position.

[0018] The roller 4 is rotatably pivoted on one end of a lever 9. The lever 9 is rockably pivoted on a double holder 10. The double holder 10 is fixed to a stand 12 with the vertical and horizontal positions of the double holder 10 against the stand 11 made adjustable, where the stand 12 is disposed standing on a frame 11 of the centerless grinder 1. The lever 9 has a spring 13 disposed between the opposite end of the lever 9 and the double holder 10, to energize, or provide force to, the roller 4 downward in the vertical direction.

[0019] An arm 14 is extended upward in the vertical direction from the contact surface 7 of the stopper 6, where the upper end of the arm 14 is swingably pivoted on the upper end of the bracket 15. The double holder 10 has its vertical and horizontal positions against the stand 11 adjusted, so that the roller 4 is arranged to have the axis thereof positioned in the same vertical plane as containing the front end surface of the preceding work 2 having been completely pushed out of the guide plate 3, and is arranged to have the lower end thereof positioned slightly lower than the upper end of the circumferential surface of the preceding work 2 before the preceding work 2 has been completely pushed out of the guide plate 3, and the stopper 6 is arranged to have the contact surface 7 thereof positioned in the same vertical plane as containing the front end surface of the preceding work 2 that has been completely pushed out of the guide plate 3, respectively.

[0020] As shown in FIG. 3, in case that a following work 2 a that is immediately following the preceding work 2 is coming out of the front end of the guide plate 3 before the preceding work 2 is caused to fall, the contact surface 7 of the stopper 6 is contacted and pushed backward, or in the direction of works 2, 2 a being pushed out of the front end of the guide plate 3, by the front end surface of the preceding work 2, which in turn causes the arm 14 to swing from the free position, thereby generating horizontal component force that pushes back the preceding work 2. This pushing-back component force is nearly in proportion to the length by which the following work 2 a protrudes from the front end of the guide plate 3, and is arranged to resist the following work 2 a being pushed out of the guide plate 3. Thus, the following work 2 a is unable to have been completely pushed out of the guide plate 3. In the meantime, upon having been completely pushed out of the guide plate 3 and pressed downward by the energized roller 4, the preceding work 2, falls downward along the contact surface 7 by means of its own weight. Therefore, the problem of double discharging of works is prevented from occurring, that the preceding, or front work and the following work fall double, or together.

[0021] The method and apparatus of the present invention may exhibit outstanding advantageous effects when applied to cases of discharging from a centerless grinder works having the axial thickness far smaller than the outer diameter, as shown in FIGS. 1 and 3, including thin-thickness works, such as valve sheets, and miniature bearing rings.

[0022] While ring-shaped works are shown in the figures referred to in the description above according to the present invention, the method and apparatus of the present invention can be applied to works other than ring-shaped, such as disk-shaped works, works having an axially recessed groove, works having an axially arc-shaped groove, and works of axially stepped shape.

[0023] With method and apparatus for discharging works from a centerless grinder implemented as described above, outstanding advantages are effected in that the following work, that is immediately following the preceding or front work, is prevented from falling together with the preceding work, in case that the following work is being pushed out of the front end of the guide plate together with the preceding work, as contrasted with conventional methods and apparatus that were unable to prevent two neighboring works from falling together. This is so effected because, if the following work is pushed out of the front end of the guide plate together with the preceding work before the preceding work, having been completely pushed out, is caused to fall, the stopper, in contact with the front end surface of the preceding work, is caused to swing from its free position, which in turn causes a swing back motion, originating a horizontal component force on the contact surface resisting and pushing back the works, whereby the following work is prevented from having been completely pushed out until the preceding work falls down.

[0024] Furthermore, because two neighboring works are not likely to fall together even when the processing speed of a centerless grinder is made greater than before, the present invention exhibits extraordinary effects in that such increase in the processing speed of a centerless grinder may enable to enhance the productivity and reduce the processing cost.

[0025] While there have been shown and described fundamental novel features of the invention as applied to preferred embodiments thereof, it will be understood that various modifications and changes to such embodiments may be made by those skilled in the art without departing from the spirit of the invention. It is our intention, therefore, to be limited only as indicated by the scope of the claims appended hereto. 

What is claimed is:
 1. A method for discharging works (2, 2 a) from a centerless grinder (1), wherein said works are through-fed to said centerless grinder (1), processed with grinding therein, aligned axially along the horizontal direction on a guide plate (3) disposed on the discharging side of said centerless grinder (1), and pushed out of the front end of said guide plate (3) by means of thrust force provided during the grinding, whereby said works (2) are caused to fall, by means of the own weight thereof, onto a discharge chute (5) disposed below, wherein said method comprises steps of: (a) pressing downward vertically the upper end of the circumferential surface of a preceding work (2) of said works being pushed out of said guide plate (3) by means of a roller (4) energized with a spring (13), and (b) causing said preceding work (2), that has been completely pushed out of said guide plate (3), to fall, while bringing the front end of said preceding work (2), that has been completely pushed out of said guide plate (3), in contact with the contact surface (7) of a stopper (6) that hangs in front of said front end of said guide plate (3), swingably in the direction of said works (2) being pushed out, wherein said stopper (6) is adapted not to swing in case that only said preceding work (2) has been completely pushed out of said front end of said guide plate (3), and said stopper (6) is adapted to swing in case that one following work (2 a) of said works, that is immediately following said preceding work (2), is being pushed out of said front end of said guide plate (3) together with said preceding work (2), whereby the horizontal component force from said stopper (6), caused by said swinging motion, prevents said following work (2 a) from being pushed out together with said preceding work (2).
 2. A method for discharging works (2, 2 a) from a centerless grinder (1) according to claim 1, wherein said roller (4) has the axis thereof positioned in the same vertical plane as containing said front end surface of said preceding work (2) that has been completely pushed out of said guide plate (3), and said roller (4) has the lower end thereof positioned slightly lower than the upper end of the circumferential surface of said preceding work (2) before having been completely pushed out of said guide plate (3), respectively.
 3. A method for discharging works (2, 2 a) from a centerless grinder (1) according to either one of claims 1 and 2, wherein said stopper (6) has said contact surface (7) thereof positioned in the same vertical plane as containing said front end surface of said preceding work (2) that has been completely pushed out of said guide plate (3).
 4. An apparatus for discharging works (2, 2 a) from a centerless grinder (1), wherein said works are through-fed to said centerless grinder (1), processed with grinding therein, aligned axially along the horizontal direction on a guide plate (3) disposed on the discharging side of said centerless grinder (1), and pushed out of the front end of said guide plate (3) by means of thrust force provided during the grinding, to be caused to fall, by means of the own weight thereof, onto a discharge chute (5) disposed below, wherein said apparatus comprises: (A) a roller (4) for pressing downward vertically the upper end of the circumferential surface of a preceding work (2) of said works being pushed out of said guide plate (3), and (B) a stopper (6) equipped with a contact surface (7) thereof for making contact with the front end of said preceding work (2) that has been completely pushed out of said guide plate (3), wherein said stopper (6) hangs in front of said front end of said guide plate (3), swingably in the direction of said works (2) being pushed out, said stopper (6) is adapted not to swing in case that only said preceding work (2) has been completely pushed out of said front end of said guide plate (3), and said stopper (6) is adapted to swing in case that one following work (2 a) of said works, that is immediately following said preceding work (2), is being pushed out of said front end of said guide plate (3) together with said preceding work (2), whereby the horizontal component force, caused by said swinging motion, prevents said following work (2 a) from being pushed out together with said preceding work (2).
 5. An apparatus for discharging works (2, 2 a) from a centerless grinder (1) according to claim 4, wherein said apparatus has a stand (12) disposed standing near said front end of said guide plate (3), said stand (12) having a lever (9) fixed thereto, by means of a double holder (10), said lever (9) including a rocking center, one end on the side of said front end of said guide plate, and the opposite end, whereby said lever (9) is fixed with the vertical position and said rocking center position of said lever (9) are adjustable, said lever (9) having said roller (4) rotatably pivoted on said one end thereof, said lever (9) having a spring (13) disposed between said opposite end thereof and said double holder (10), whereby said spring energizes said roller (4) to press down said preceding work (2) being pushed out of said guide plate (3).
 6. An apparatus for discharging works (2, 2 a) from a centerless grinder (1) according to claim 4, wherein said apparatus has a stand (12) disposed standing near said front end of said guide plate (3), said stand (12) having a bracket (15) fixed thereto, said bracket (15) being extended upward, said bracket (15) having the upper end of said stopper (6) swingably pivoted on the upper end of said bracket (15), said stopper (6) having the lower end thereof equipped with said contact surface (7) that makes light contact, under the free conditions, with said front end of said preceding work (2) that has been completely pushed out of said guide plate (3), said stopper (6) having the lower end thereof further extended downward to form a guide surface (8) approximately in parallel with said discharge chute (5).
 7. An apparatus for discharging works (2, 2 a) from a centerless grinder (1) according to claim 5, wherein said stand (12) disposed standing near said front end of said guide plate (3); having a bracket (15) fixed thereto, said bracket (15) being extended upward, said bracket (15) having the upper end of said stopper (6) swingably pivoted on the upper end of said bracket (15), said stopper (6) having the lower end thereof equipped with said contact surface (7) for making light contact with said front end of said preceding work (2) that has been completely pushed out of said guide plate (3), said stopper (6) having the lower end thereof further extended downward to form a guide surface (8) approximately in parallel with said discharge chute (5).
 8. An apparatus for discharging works (2, 2 a) from a centerless grinder (1) according to either one of claims 4-7, wherein said roller (4) has the axis thereof positioned in the same vertical plane as containing said front end surface of said preceding work (2) that has been completely pushed out of said guide plate (3), and said roller (4) has the lower end thereof positioned slightly lower than the upper end of the circumferential surface of said preceding work (2) before having been completely pushed out of said guide plate (3), respectively.
 9. An apparatus for discharging works (2, 2 a) from a centerless grinder (1) according to either one of claims 4-7, wherein said stopper (6) has said contact surface (7) thereof positioned in the same vertical plane as containing said front end surface of said preceding work (2) that has been completely pushed out of said guide plate (3).
 10. An apparatus for discharging works (2, 2 a) from a centerless grinder, (1) according to claim 8, wherein said stopper (6) has said contact surface (7) thereof positioned in the same vertical plane as containing said front end surface of said preceding work (2) that has been completely pushed out of said guide plate (3). 